README.md

Noir with Foundry

This example uses Foundry to deploy and test a verifier.

Getting Started

Want to get started in a pinch? Start your project in a free Github Codespace!

In the meantime, follow these simple steps to work on your own machine:

Install noirup with

1. Install noirup:

   curl -L https://raw.githubusercontent.com/noir-lang/noirup/main/install | bash

2. Install Nargo:

   noirup

3. Install foundryup and follow the instructions on screen. You should then have all the foundry tools like forge, cast, anvil and chisel.

curl -L https://foundry.paradigm.xyz | bash

4. Install the correct version of the Barretenberg proving backend for Noir (bb).

   curl -L https://raw.githubusercontent.com/AztecProtocol/aztec-packages/master/barretenberg/cpp/installation/install | bash

   then

   bbup -v 0.41.0 # compatible with nargo 0.31.0

Generate verifier contract and proof

Contract

The deployment assumes a verifier contract has been generated by nargo. In order to do this, run:

cd circuits
nargo compile
bb write_vk -b ./target/with_foundry.json
bb contract

A file named contract.sol should appear in the circuits/target folder.

Proof

You also need a proof, as this template currently doesn't employ ffi to call nargo execute (to generate the witness) and bb prove by itself. For this, ensure your prover parameters are correct in Prover.toml and run:

bb prove -b ./target/with_foundry.json -w ./target/witness.gz -o ./target/with_foundry.proof

A file named with_foundry.proof should appear in the ./circuits/target folder.

Test with Foundry

We're ready to test with Foundry. There's a basic test inside the test folder that deploys the verifier contract, the Starter contract and two bytes32 arrays correspondent to good and bad solutions to your circuit.

By running the following command, forge will compile the contract with 5000 rounds of optimization and the London EVM version. You need to use these optimizer settings to supress the "stack too deep" error on the solc compiler. Then it will run the test, expecting it to pass with correct inputs, and fail with wrong inputs:

forge test --optimize --optimizer-runs 5000 --evm-version london

Testing On-chain

You can test that the Noir Solidity verifier contract works on a given chain by running the Verify.s.sol script against the appropriate RPC endpoint.

forge script script/Verify.s.sol --rpc-url $RPC_ENDPOINT  --broadcast

If that doesn't work, you can add the network to Metamask and deploy and test via Remix.

Note that some EVM network infrastructure may behave differently and this script may fail for reasons unrelated to the compatibility of the verifier contract.

Deploy with Foundry

This template also has a script to help you deploy on your own network. But for that you need to run your own node or, alternatively, deploy on a testnet.

(Option 1) Run a local node

If you want to deploy locally, run a node by opening a terminal and running

anvil

This should start a local node listening on http://localhost:8545. It will also give you many private keys.

Edit your .env file to look like:

ANVIL_RPC=http://localhost:8545
LOCALHOST_PRIVATE_KEY=<the private key you just got from anvil>

(Option 2) Prepare for testnet

Pick a testnet like Sepolia or Goerli. Generate a private key and use a faucet (like this one for Sepolia) to get some coins in there.

Edit your .env file to look like:

SEPOLIA_RPC=https://rpc2.sepolia.org
LOCALHOST_PRIVATE_KEY=<the private key of the account with your coins>

Run the deploy script

You need to source your .env file before deploying. Do that with:

source .env

Then run the deployment with:

forge script script/Starter.s.sol --rpc-url $ANVIL_RPC --broadcast --verify

Replace $ANVIL_RPC with the testnet RPC, if you're deploying on a testnet.

Developing on this template

This template doesn't include settings you may need to deal with syntax highlighting and IDE-specific settings (i.e. VScode). Please follow the instructions on the Foundy book to set that up.

It's highly recommended you get familiar with Foundry before developing on this template.